AVR Gameboy Dumper

[Kevan] has been hard at work latley developing a Gameboy cart dumper, and while there are a few loose ends to tie up, the device is functioning fine to build up his collection. Running an AVR (mega 16?) and a FTDI chip for the usb connection, the device reads the game’s ROM and SRAM, and can also write the SRAM if you want to load your save games on to the real cart.

On the pc side of things, the device is communicated with using a generic HID protocol and can hit speeds from 16Kbps (currently) to around 64Kbps (soon). A python script currently handles the data stream, but for the rest of us there is a GUI version in the works for both *x and windows.

Also in the works is a redesigned PCB. There were a couple issues and you can see the jumpers, and though we think it adds a little character, it would be good to have fixed in the future.

I don’t think there’s an FTDI chip on there — he mentions that he tried to use the factory bootloader of the AVR, which makes me think he’s using a hardware-USB-enabled chip (AT90USB or similar). I also see no FTDI chip on the board, and I don’t know of any FTDI chips that use generic HID (AKA don’t need drivers), as this one apparently does. Looks pretty spiffy, it might be interesting to try out making a version with a software USB library (since I doubt the full speed of a USB AVR is necessary for this task). Also would be interesting to try to make it appear to be a USB Key or something; it’d make for easier ROM dumping. Very cool, though!

I like the fact that there’s no (silly) FTDI chip, but posing as a HID device is just wrong. In fact, these blatant abuses of the USB HID profile are far too common (lookin’ at you, Arduino!) and just need to stop. This should be a vendor-specific device (class 0xFF) or perhaps CDC (like a serial port, but that’s not quite right either.) Hardware like this needs a driver, period; the right thing to do is write a good (userspace) one that can be trivially ported to various platforms and bridged to various languages.

It is a ATMEGA32U4, I chose to start off with just the Generic HID diver just to verify that the hardware part of the project is working correctly. I do plan on writing a custom driver for it to speed up dumping speeds considerably.

Kuy: unfortunately, the only practical way to write userspace drivers on older versions of Windows was to make your USB hardware a HID device. So basically, you can thank Microsoft for this widespread abuse of the HID class.